A Rare Case of Fat Embolism Syndrome Masquerading as COVID-19 Pneumonia.

In the wake of the novel coronavirus disease 2019 (COVID-19) pandemic and its associated mortality and virulence, a high clinical suspicion must be maintained for all patients presenting with respiratory failure. However, there are well-known disease processes that may have a similar presentation. We present a case of a 25-year-old male who suffered a right tibia fracture after a motor vehicle collision. He had acute hypoxic respiratory failure within 24 hours of admission, requiring mechanical ventilation. His condition significantly improved with airway pressure release mode of ventilation and proning. Although his chest CT demonstrated characteristic findings of COVID-19, he subsequently tested negative. The differential included aspiration pneumonia and fat embolism syndrome from the lower extremity fracture. Fat embolism syndrome can very closely mimic COVID-19. The rapid onset and improvement of symptoms coupled with serial negative COVID-19 testing may aid in the diagnosis.